Managing Database Files (Oracle)

Use

To improve availability and performance, you need to manage your database files and their distribution. An Oracle database consists of control files, redo log files and data files. Control files and redo log files can be mirrored at the Oracle software level.

We make recommendations here on file distribution for performance (that is, I/O load balancing) as well as for high availability. This is because a poorly balanced system might necessitate a reorganization of the database or redistribution of data files, so causing downtime (however, redistribution of data files requires only short downtime).

Make sure the system is correctly balanced from the outset so as to avoid both performance and high availability problems later. Load balancing is a complex area so make sure that your intended alteration will actually bring about the desired improvement.

Procedure

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       1.      Set up the control files and redo log files correctly.

SAP recommends having at least three control files and two members (that is, copies) in each redo log group. From the high availability viewpoint, place the three control files on different disks. In the same way, separate the two members of a redo log file group on different disks. This makes sure that a single disk failure does not lead to the loss of all control files or of all members of a redo log group.

       2.      Use the SAP disk space configuration program.

You should use SAP’s disk space configuration program to estimate table and tablespace growth for each business application. This allows you to configure your disks correctly from an early stage, so avoiding problems later.

       3.      Inspect SAP ABAP TABLE buffers before database.

Focus on SAP ABAP TABLE buffers as performance levers because the database is usually an insignificant factor towards the poor performance detected by the end user.

       4.      Use BRSPACE to reorganize tablespaces.

If your system appears to be unbalanced it might be sensible to reorganize the tablespace and its data files using BRSPACE. Make sure that you have correctly interpreted the problem. For more information about reorganization, see Reorganizing Objects (Oracle).

Result

Your system is optimally balanced in terms of file distribution and disk I/O, so improving performance reducing downtime for the database and the SAP system.